Question

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Answer 1

Problem 18

Answers:

~P -> Q: "if it is not fall, then the leaves change colors"

~P -> ~Q: "if it is not fall, then the leaves don't change colors"

P -> ~Q: "If it is fall, then the leaves don't change colors"

Q -> ~P: "If the leaves change colors, then it is not fall"

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Explanation:

Simply replace each letter with the corresponding definition. We replace each P with "it is fall" and each ~P with "it is not fall". The squiggly line means "not". The same idea applies with Q and ~Q.

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Problem 19

Answer: Choice A) 134

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Explanation:

AB = CD

8x = 4x+24

8x-4x = 24

4x = 24

x = 6

BC = 18x+26

BC = 18*6+26

BC = 134

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Problem 20

Answer: Choice C) x = 5 and y = 11

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Explanation:

(anglePQR)+(angleRQS) = 90

(12x-2)+(6x+2) = 90

18x = 90

x = 5

angle TQU = 90

10y-20 = 90

10y = 110

y = 11

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Problem 21

Answer:  99

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Explanation:

The remote interior angles add to the exterior angle (remote interior angle theorem)

(angle RPQ) + (angle PQR) = angle PRS

(3x-29) + (7x-42) = 6x-3

10x-71 = 6x-3

10x-6x = -3+71

4x = 68

x = 68/4

x = 17

angle PRS = 6x-3

angle PRS = 6*17-3

angle PRS = 99

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Problem 22

Answer: 116

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Explanation:

Refer to the diagram below.

Solve 105+x = 180 to get x = 75

Solve 135+y = 180 to get y = 45

Solve x+y+z = 180 to get z = 60

Solve z+82+p = 180 to get p = 38

Solve p+78+q = 180 to get q = 64

Solve q+r = 180 to get r = 116

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Problem 23

Answer: B) between 4 and 44 inches

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Explanation:

We use a variation of the triangle inequality theorem here.

If p is the missing side length, then

24-20 < p < 24+20

4 < p < 44

So,

4 < XY < 44

The side XY cannot be 4 inches and it cannot be 44 inches either.

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Problem 24

4 Answers: A, B, C, D

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Explanation:

Same idea as problem 23

24-10 < x < 24+10

14 < x < 34

So we'll select values between 14 and 34, excluding each endpoint. Those values are x = 16, 18, 24, 26

In other words, only 12 and 34 are non-answers.

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Problem 25

Answer: C) 84 degrees

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Explanation:

The given exterior angle is 152 degrees

Subtract that from 180 to get the adjacent interior angle 180-152 = 28

Now let's find the missing angle of triangle DEB

D+E+B = 180

28+68+B = 180

96+B = 180

B = 180-96

B = 84

This is the measure of angle DBE

This is also the measure of angle ABC because the two angles are vertical angles.

Vertical angles are always congruent.